Striker for printing chronocomparator diagrams

ABSTRACT

A striking device for use in printing diagrams in a chronocomparator includes a striker head and electromagnetic means responsive to electrical control pulses for moving said striker head into contact with a recording or printing web. The electromagnetic means includes a rigid metal frame having a central magnetic core mounted therein and cooperating therewith to define an annular gap in a magnetic circuit. An iron-less coil is movably mounted in this gap and rigidly secured to the striker head. The coil is adapted to be operatively connected to a source of control pulses whereby upon receipt of a control impulse the coil reciprocates in the gap to move the striker head.

v United States Patent 1191" 11] 3,787,890 Bonny Jan. 22, 1974 STRIKER FOR PRINTING 2,646,518 7/1953 Thompson 346/101 x C O OCO DlAGRAMS 3,149,902 9/1964 Dransfield 346/ 141 X [75] Inventor g i s g a ggzfi La Chaux dc Primary ExaminerJoseph W. Hartary Attorney, Agent, or Firm-Arthur V. Smith [73] Assignee: Portescap, La Chaux de Fonds,

Switzerland 7 [57] ABSTRACT [22] Flled: June 14, 1972 A k d f v t d str1 mg evice or use 1n prm mg 1agrams 1n a [21} Appl 262609 chronocomparator includes a striker head and electromagnetic means responsive to electrical control pulses [30] Foreign Application Priority Data for moving said striker head into contact with a re- June 16, 1971 Switzerland 8768/7] cording Priming The electromagnetic means 7 includes a rigid metal frame having a central magnetic 52 US. 01 "346/141, 335/222, 335/277, we mmmted therein and woperafing therewith to 346/101 define an annular gap in a magnetic circuit. An iron- 51 1111. C1. .1 G0ld 15/24 less coil is "mvably mounted in this gap and rigidly 5 Field of Search 346/101 141;-335l222, 277 cured to the striker head. The coil is adapted to be operatively connected to a source of control pulses 5 References Cited whereby upon receipt of a control impulse the coil reciprocates in the gap to move the striker head.

8 Claims, 2 Drawing Figures STRIKER FOR PRINTING CHRONOCOMPARATOR DIAGRAMS The present invention relates to a striking device for printing chronocomparator diagrams, and in particular to a striker actuated by. an electromagnetic device which is operative in response to a drive pulse to mark a point on a recording strip which advances between the striker and a helix drum.

Apparatus for testing or checking the rate of clocks and watches, commonly known as chronocomparators, typically form a diagram of a series of aligned points on a recording strip. Each of these points corresponds to a given moment of the operating period of a component of the clock or watch, so that as the recording tape is driven at a constant speed, the inclination of a line formed by the points made by the chronocomparator is a measure of the running rate of the clock or watch.

Previously proposed chronocomparators use striking devices that include electromagnetic devices which receive control pulses from a detector to drive a movable armature secured to the striker head. In such devices, the parts for the mechanical transmission of the striking movement are rather bulky and have a substantial inertia. Because of this, and because of the hysteresis effect of the magnetization of the armature, the striking extends over a relatively long period of time. Accordingly, since the striking time limits the speed of scanning, the precision of the chronocomparator is a function of this striking time and the operation of the electromagnetic device. Moreover, if the speed of the drum on which the striker prints is increased beyond this limit, the points printed by the head are deformed into small dashes, which prevents a precise reading of the diagram.

Accordingly, it is an object of the present invention to overcome the drawbacks of such previously proposed striking devices.

It is another object of the invention to provide a compact striking device which makes it possible to reduce the printing time in a chronocomparator.

Yet another object of the present invention is to provide a device of the character described which is relatively simple and inexpensive to manufacture.

The above, and other objects, features and advantages of this invention will be apparent in the following detailed description of an illustrative embodiment thereof which is to'be read in connection with the accompanying drawings, wherein:

FIG. 1 is an elevational view, partly in section, of a striking device, constructed in accordance with a preferred embodiment of the present invention, as seen in the direction of advance of the recording strip, and with parts broken away; and

FIG. 2 is a side view, taken along line 2--2 in FIG. 1 and showing the striking device mounted above a recording strip and helix drum.

Referring now to the drawings, it will be seen that a striking device 1 constructed in accordance with the present invention includes a fixed housing or frame H and a moving portion or striker head 2. Thestriker head device is mounted in housing H for reciprocation with respect to a cylindrical drum 3 whose surface is provided with a plurality of helicoidal protrusions 4 extending over the entire width of the drum. Between drum 3, which rotates with a constant speed, and striker 2, there passes a recording strip or web 5 and an inking ribbon (not shown). Striker head 2 is provided on its lower surface with an edge 6 that, during any given stroke of the head, cooperates with one of the protrusions 4 to print a point on the strip 5.

A coil-holder disk 7 is rigidly connected with striker 2 and an iron-less coil 8 is secured thereto. In addition, two hollow vertical tubes 9, 10 are rigidly secured (e. g., by inner screws, not shown) to striker 2, and operatively interconnected by a plate 11 secured to their upper ends. Plate 11 is in turn, connected to striker head 2 by a central rod 12 which increases the rigidity of the moving system.

The stationary housing I-I forms a magnetic circuit and includes an axially magnetized cylindrical permanent magnet 13, and coaxial, cylindrical or pot-shaped pole piece 14. The latter is secured at its lower edge to a coaxial annular disk 15 and magnet 13 is secured to a cylindrical coaxial pole piece 16. The entire assembly is covered by a cap 17 which is secured to cylinder 14 in any convenient manner.

Members 14 and 15 have openings 18, 19 formed therein to permit the free passage of tubes 9 and 10; and members l3, 14, 16 have axially aligned apertures therein to permit the free passage of rod 12.

The inner cylindrical surface 15' of the disk 15 and the peripheral surface 16' of cylindrical part 16 cooperate to define a gap 20 which receives a coil 8. The latter is formed of a cylindrical, thin winding, the lower edge of which is secured to disk 7 in any convenient manner, e.g., by an adhesive. As mentioned, disk 7 is rigidly connected 'with the striker head 2. In addition, winding or coil 8 is electrically connected by flexible wires (not shown) to the source of the printing control pulses, that is, to the detector device of the chronocomparator.

Striker 2 is suspended by means of two leaf springs 21, 22 in the form of conventional spring washers. Spring 21 is fastened by screws 23, 24 to housing H at two diametrically opposite points and is also camped between striker 2 and vertical tubes 9, 10. Spring 22 in similar fashion, is secured to housing H and to tubes 9, 10, to suspend the striker head from the upper part of the striking device.

When coil 8 is traversed by a current pulse of suitable polarity, the interaction of this current and the radial magnetic field in which the coil is placed leads to an axial displacement of the coil and therefore of the entire moving system in the direction indicated by the arrow in FIG. 1, against the return force of the springs 21, 22. The striker is thus projected towards the surface of the drum 3 and its edge 6 prints a point on the tape 5 at the intersection of the edge with the helicoidal edge 4 which forms an anvil cooperating with edge 6.

Vertical tubes 9, 10, secured to striker 2, each contain a stack of disks 25 which can move axially within the tubes. Upon engagement of edge 6 with web 5 and edge 4, the movement of these disks with respect to the striker absorbs in particular the kinetic energy of rebound of the striker due to the elasticity of the assembly of supports and suspensions and dampens all the vibrations of the moving system.

The striking device described makes it possible to print well defined single points with a high speed of the recording strip. This is essentially the result of the use of an iron-less coil and of the small mass of the moving system which make it possible to attain an extremely short printing time. Further, the dampening of the movement of the striker avoids a double printing per pulse on the recording strip and the coaxial construc tion leads to a compact assembly which can easily be integrated in the chronocomparator.

Although an illustrative embodiment of the present invention has been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to that precise embodiment and that various changes and modificatins may be effected therein by one skilled in the art without departing from the scope or spirit of this invention.

What is claimed is:

l. A striking device for use in printing diagrams in a chronocomparator, said device comprising a striker head and electromagnetic means, operative in response to electrical control pulses and operatively connected to said striker head, said electromagnetic means including a rigid metal frame, a central magnetic core mounted in said frame and cooperating therewith to define an annular gap in a magnetic circuit, an iron-less coil movably mounted in said gap and secured to said striker, said coil being adapted to be operatively connected to a source of said control pulses whereby upon receipt of a control pulse said coil reciprocates in said gap and moves said striker head; at least one hollow tube secured to said striker head and extending therefrom into said frame parallel to the direction of movement of said coil, and a plurality of individual disks contained in said tube, said disks being adapted to move in said tube axially with respect to said striker to absorb the kinetic energy of the rebound of the striker at the end of its movement by said coil to dampen vibrations in the device. 1

2. The device as defined in claim 1 including at least one spring operatively connected between said frame and said striker for biasing said striker to a first position opposite to the direction of movement of said coil upon receipt of a control pulse.

3. The device as defined in claim 2 wherein said spring comprises a spring washer.

4. The device asdefined in claim 3 including a pair of hollow tubes operatively connected at one end to said striker head, said tubes extending through said frame and being rigidly interconnected at their opposed ends.

5. The device as defined in claim 4 including a second spring washer operatively connected between said frame and said tubes for biasing said striker head in said first direction.

6. The device as defined in claim 5 including a plurality of individual disks contained in said tubes and adapted to move therein axially with respect to the striker in the direction of movement thereof.

7. A striking device for use in printing diagrams in a chronocomparator, said device comprising an elongated striker head' and electromagnetic means, operative in response to electrical control pulses and operatively connected to said striker head, said electromagnetic means including a rigid metal frame, a central magnetic core mounted in said frame and cooperating therewith to define an annular gap in a magnetic circuit, an iron-less coil movably mounted in said gap and secured to said striker, said coil being adapted to be operatively connected to a source of said control pulses whereby upon receipt of a control pulse said coil reciprocates in said gap and moves said striker head; a central rod rigidly secured to said striker head and extending freely through said central magnetic core within said coil, a pair of tubes operatively connected in spaced relation to said striker head at diametrically opposed points adjacent said coil, said tubes extending freely through said frame and being rigidly interconnected at their opposite ends to each other and to said central rod to define an integral guide structure for said head, and a pair of spring washers respectively operatively connected to said frame and to opposite ends of said tubes, said spring washers both biasing said head in the same direction opposite to the direction of movement of said coil upon receipt of a control pulse.

8. The device as defined in claim 7 wherein said tubes are hollow and contain a plurality of individual disks adapted to move in said tube axially with respect to said striker to absorb the kinetic energy of the striker at the end of its movement by said coil to dampen vibrations in the device. 

1. A striking device for use in printing diagrams in a chronocomparator, said device comprising a striker head and electromagnetic means, operative in response to electrical control pulses and operatively connected to said striker head, said electromagnetic means including a rigid metal frame, a central magnetic core mounted in said frame and cooperating therewith to define an annular gap in a magnetic circuit, an iron-less coil movably mounted in said gap and secured to said striker, said coil being adapted to be operatively connected to a source of said control pulses whereby upon receipt of a control pulse said coil reciprocates in said gap and moves said striker head; at least one hollow tube secured to said striker head and extending therefrom into said frame parallel to the direction of movement of said coil, and a plurality of individual disks contained in said tube, said disks being adapted to move in said tube axially with respect to said striker to absorb the kinetic energy of the rebound of the striker at the end of its movement by said coil to dampen vibrations in the device.
 2. The device as defined in claim 1 including at least one spring operatively connected between said frame and said striker for biasing said striker to a first position opposite to the direction of movement of said coil upon receipt of a control pulse.
 3. The device as defined in claim 2 wherein said spring comprises a spring washer.
 4. The device as defined in claim 3 including a pair of hollow tubes operatively connected at one end to said striker head, said tubes extending through said frame and being rigidly interconnected at their opposed ends.
 5. The device as defined in claim 4 including a second spring washer operatively connected between said frame and said tubes for biasing said striker head in said first direction.
 6. The device as defined in claim 5 including a plurality of individual disks contained in said tubes and adapted to move therein axially with respect to the striker in the direction of movement thereof.
 7. A striking device for use in printing diagrams in a chronocomparator, said device comprising an elongated striker head and electromagnetic means, operative in response to electrical control pulses and operatively connected to said striker head, said electromagnetic means including a rigid metal frame, a central magnetic core mounted in said frame and cooperating therewith to define an annular gap in a magnetic circuit, an iron-less coil movably mounted in said gap and secured to said striker, said coil being adapted to be operatively connected to a source of said control pulses whereby upon receipt of a control pulse said coil reciprocates in said gap and moves said striker head; a central rod rigidly secured to said striker head and extending freely through said central magnetic core within said coil, a pair of tubes operatively connected in spaced relation to said striker head at diametrically opposed points adjacent said coil, said tubes extending freely through said frame and being rigidly interconnected at their opposite ends to each other and to said central rod to define an integral guide structure for said head, and a pair of spring washers respectively operatively connected to said frame and to opposite ends of said tubes, said spring washers both biasing said head in the same direction opposite to the direction of movement of said coil upon receipt of a control pulse.
 8. The device as defined in claim 7 wherein said tubes are hollow and contain a plurality of individual disks adapted to move in said tube axially with respect to said striker to absorb the kinetic energy of the striker at the end of its movement by said coil to dampen vibrations in the device. 